Automated Monitoring System for Self-Synchronizing Vibrational Drives

An automated monitoring system has been designed to maintain stable operation of self-synchronizing vibrational drives. By means of the system, information is collected and automatically processed. A built-in electrical feedback loop ensures synchronous drive operation.     

The effect of iodine-containing x-ray contrast media on water status in the blood plasma

The impact of radio-opaque agents on human blood plasma water pool was studied by using relaxation proton magnetic resonance methods with a pulse gradient of magnetic field. The findings suggest that blood plasma water imbalance was induced by human serum albumin dehydration processes after RCN-HSA interaction.     

H3-25-hydroxycholecalciferol metabolism in rats with experimental femoral fractures

At the 3d day after femoral bone fracture in rats, the concentration of 3H-25-OHD3 injected intraperitoneally 18 h before sacrifice was 25 and 60% higher in the kidneys and small intestinal mucosa, respectively, whereas the incorporation of the label in 1,25(OH)2D3 in the blood serum and small intestinal mucosa was 50 and 70% higher as compared with intact control. The binding of 3H-25-OHD3 in the diaphysis and epiphysis of the fractured bone was 2-3 times as increased at the 3d and 10th days after fracture. A similar but less marked increase in the accumulation of 3H-25-OHD3 was recorded in the paired intact bone of rats with femoral fractures. Incorporation of the label from 3H-25-OHD3 in 1,25(OH)2D3 and 24,25(OH)2D3 in the epiphyses of the fractured bone as well as in the epiphyses and diaphysis of the intact bone of rats with femoral fractures was 1.5-2 times as increased at all the times of the observation period (3, 10, 28 days after fracture).     

Characterization of Temperature-Dependent Kinetics of Oculocutaneous Albinism-Causing Mutants of Tyrosinase

Human tyrosinase (Tyr) is a glycoenzyme that catalyzes the first and rate-limiting step in melanin production, and its gene (TYR) is mutated in many cases of oculocutaneous albinism type 1 (OCA1). The mechanisms by which individual mutations contribute to the diverse pigmentation phenotype in patients with OCA1 have only began to be examined and remain to be delineated. Here, we analyze the temperature-dependent kinetics of wild-type Tyr (WT) and two OCA1B mutant variants (R422Q and P406L) using Michaelis–Menten and Van’t Hoff analyses. Recombinant truncated human Tyr proteins (residues 19–469) were produced in the whole insect Trichoplusia Ni larvae. Proteins were purified by a combination of affinity and size-exclusion chromatography. The temperature dependence of diphenol oxidase protein activities and kinetic parameters were measured by dopachrome absorption. Using the same experimental conditions, computational simulations were performed to assess the temperature-dependent association of L-DOPA and Tyr. Our results revealed, for the first time, that the association of L-DOPA with R422Q and P406L followed by dopachrome formation is a complex reaction supported by enthalpy and entropy forces. We show that the WT has a higher turnover number as compared with both R422Q and P406L. Elucidating the kinetics and thermodynamics of mutant variants of Tyr in OCA1B helps to understand the mechanisms by which they lower Tyr catalytic activity and to discover novel therapies for patients.     

Intensification of evaporation of uranium hexafluoride

The theoretical mechanism of the sublimation of uranium hexafluoride are considered. The most contribution to the rate of evaporation of UF₆ is introduced by the conductive mode of heat exchange. Various modes of the intensification of the evaporation of uranium hexafluoride during the nitrogen supply in pulse mode to the product mass are investigated. The nitrogen supply results in the turbulization of gas flow within a vessel (Re = 2500–4000) and significantly increases the rate of evaporation of uranium hexafluoride with the substantial decrease in a weight of the nonevaporable residue of 5.6–1.0 kg. The complex application of the pulse nitrogen supply in combination with heating the bottom of the vessel is the most effective method for evaporating uranium hexafluoride. The rate of evaporation of UF6 increases by a factor of almost four in comparison with the design mode. The developed methods are applied in industry and provide the stable operation of Saturn reactors during the conversion of uranium hexafluoride into its dioxide.